1. Preheat the oven to 350°F and line baking sheets with parchment paper.

2. Beat the softened butter and granulated sugar until pale, fluffy, and smooth.

3. Mix in the egg, vanilla extract, and cotton candy flavoring until creamy.

4. In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and cornstarch.

5. Add the dry ingredients to the wet ingredients and mix just until a soft dough forms.

6. Divide the dough into portions, tinting one pink and one blue with gel food coloring. Leave a small portion plain if desired.

7. Gently press small pieces of each dough color together and roll into balls without fully blending the colors.

8. Roll each dough ball lightly in powdered sugar and sanding sugar if using.

9. Chill the dough balls for 20 to 30 minutes so the cookies hold their shape.

10. Bake for 9 to 11 minutes, until the edges are set and the centers still look soft.

11. Let the cookies cool on the baking sheet for a few minutes, then transfer to a wire rack.